According to Pew Research, 49 percent of Republicans or Republican leaning voters are likely to vote this year; but among those who hold a very unfavorable view of the Democratic party, 65 percent are likely to vote. The pattern is similar in the Democratic base. The more the base dislikes Republicans, the more likely to are going to vote in the midterm.
This is another remember of how the bad design of election rules are enhancing dysfunction and producing bad policy outcomes.
Since our midterm elections are relatively low turnout by international standards, it is often more important for parties to focus on motivating their base instead of trying to win over new people with popular ideas. This means it is to a party’s advantage to dedicate themselves to increased animosity towards their opponents and make it seem like all their ideas are all terrible. This will help improve turnout in their base enabling them to win. Also, since the rules basically favor only two parties, it means a party can afford to do unpopular things as long as it makes the other party look even worse.
Of course adopting the winning political strategy makes it very difficult to work on compromise during the election season, and since we have Congressional elections every two years it is almost always the election season.
If we had election rules designed to encourage as high a turnout as possible through policies like automatic voter registration, making election day a holiday, or even mandatory voting; the incentive to increase animosity to drive turnout will be greatly reduced.
At the same time, if we had less frequent Congressional elections, like most other democracies which have terms around four to five years, there wouldn’t be the same political incentive to keep the anger toward the opposing party revved up all the time.